Fishless Cycle

Cycling Your New Aquarium Without Fish

(The First Tank Guide)

What is Aquarium Cycling?

Cycling your aquarium is the process of establishing the biological filter, a colony of
beneficial bacteria that live in the filter media and process the
fish's waste. The effects of the cycling process on fish are sometimes
referred to as "New Tank Syndrome."
New Tank Syndrome can sometimes be avoided by cycling the tank without
fish. However, New Tank Syndrome can always
be avoided by properly cycling your aquarium
with a small number of fish and keeping up with the necessary extra water changes.

How Do I Cycle MY Tank Without Fish?

To cycle your new aquarium without using fish, you need to set up your new aquarium, make sure all the
equipment is functioning and that nothing leaks, and then dechlorinate the water. Then you add some
ammonia to the tank. Make sure you use an ammonia that does not have
any added colors, perfumes, detergents or anything else that could be
harmful to your fish, your biological filter, or any of your
equipment.

You want to add enough ammonia to the tank to get your
concentration pretty high, probably around 4ppm or more, well into
the "danger" zone on most test kits. This can be done either by adding
a few drops of ammonia each day until your tank reaches this level,
then continuing to add more ammonia to the tank daily until the
nitrite levels reach 0ppm and stay there, or by adding a lot of
ammonia all at once and letting the tank sit, only beginning to add
more ammonia to the tank when the ammonia level begins to drop.

How Do I Know If There Is Enough Ammonia in the Tank?

With fishless cycling, you will need to do a lot of testing. To
start with, you will need to test for ammonia daily to see what your
ammonia level is, and whether or not you need to add more ammonia
yet. Once the ammonia levels in your tank begin to drop, you will need
to add more ammonia daily until the nitrite levels stay steady at 0ppm
and you are ready to get fish. So, once your ammonia levels start to
drop, you have to start testing for both ammonia (to make sure the
levels are staying up) and nitrite (to watch for the increase and then
decrease in nitrite levels).

Remember, it is vitally important to the process that you not let
the tank reach 0ppm ammonia before you add your fish. You'll need to
test for ammonia at least daily once the ammonia levels start to
drop.

When Is My Tank Ready for Fish?

Your tank is ready to add fish when your ammonia tests are quickly
dropping over the course of a day, and your nitrite level has risen
and subsequently dropped back to 0ppm.

Once you reach this point, you are ready to add your first
fish. However, before you add your first fish, you need to do a water
change to eliminate excess nitrate buildup in the tank (since you have
been neglecting your regular water changes up to this point) and to
remove the extra ammonia you have been adding. This will usually be a
50% or greater water change.

After you perform this large water change, you have just a few
hours to get fish into the tank to start producing waste to keep the
biological filter healthy.

What Are the Drawbacks to Fishless Cycling?

This is a topic you won't see covered in many places, especially
those that are promoting fishless cycling.

There are several drawbacks to fishless cycling, especially for a
beginner.

There are a number of other processes that go on in the tank and
the filter that this process doesn't address, primarily handling of
other organic material produced in the fish's metabolism. In fact, the
high ammonia levels you have maintained in the tank can prevent some of
these other processes from starting, even if there is a waste source
for them to use (such as decaying fish food or a piece of meat). Of
course, adding another waste source to the tank could result in a
messy, cloudy, or otherwise unsuitable
aquarium environment. Also, the high ammonia levels will keep the
oxygen levels low, preventing the filter from operating at a good
efficiency.

Often, when cycling a tank without fish, you lose the biological filter between when you
think the filter is ready and when you get fish, meaning after going
through several weeks without fish in the tank to get the tank cycled
without fish, you introduce fish to an uncycled tank anyway, resulting
in stress and losses.

Also, since some of the other processes that are not ready when you
introduce fish because you haven't had fish and fish waste in the tank
are not ready, which can cause problems, leaving you with the same
process you would have gone through with a limited number of fish and
a lot of water changes, or significant risk to your fish when you do
get fish.

On top of that, you need to do a lot of testing, learn how to read the
test results, and understand what the tests are telling you. This
shouldn't really be necessary when cycling with fish. If you cycle with fish, you may want to get the water
tested once or twice during the process (though it isn't really
necessary), but usually a pet shop will do
that free or cheap. Even when you are testing your tank while cycling
without fish, you're often going 8-16 hours between tests, leaving
enough time for the filter to significantly collapse.

On top of all this, if you are cycling with
fish and keeping up with the water
changes, the fish will indicate stress to you much sooner than
you'd read it on a test kit - and they'll actually indicate stress to
you, rather than a test that says that there may be a stressful level
of ammonia or nitrite in the water - and you can quickly correct this
potentially stressful situation with a water change. Of course, if you
are keeping up with the necessary water changes and aren't using too
many fish, your ammonia will never reach a stressful level while the
tank is cycling.

Cycling the tank with fish always results in a cycled tank (assuming
the tank is large enough to cycle), but cycling without fish may or
may not leave you with a cycled tank, and the only way to tell is to
add fish.

Cycling the tank with fish minimizes the work you need to do, and
minimizes the things you need to do and understand to get your tank
running and stable.

Cycling the tank with fish poses little, if any, risk to the fish,
assuming you follow three simple rules: few fish, minimal feeding, and
plenty of water changes. Cycling the tank without fish may pose no
risk to your fish, but may also pose much greater risk to your fish
than cycling with fish.

Why Are Some People Against Cycling with Fish?

Most people who are adamantly against cycling a tank with fish are
thinking of the bad old days (or anyone who visits PetsMart, PetCo, or
other bad pet shops) and gets the
recommendation to just dump a bunch of feeder goldfish (I've heard as many as two
fish per gallon of water) into the tank to cycle it, and not to do any
water changes for one to two months. This is very, VERY bad advice,
and certainly would not be recommended by anyone who is interested in
the stability of your tank or the well being of the fish in
question. And, yes, fishless cycling is almost certainly better than
that approach. However, cycling with a small number of hearty fish and
keeping up with the water changes is definitely going to be easier,
less frustrating, and pose less risk to your fish than fishless
cycling.

Check out these pages to help you get started with your first fish
tank:

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